Question:
I purchased a Kenmore refrigerator ( made by Whirlpool ) last yeat that has a replaceable water filter mounted through the grille.

I have been buying filters that process 500 gallons: they are expensive, about $30. The refrigerator has an indicator monitor that supposedly measures the amount of water that passes through the filter. It tells you when to replace the filter. It just indicated I am to replace the filter after six months of use.

But is this the truth? . I absolutely do not use that much water, the most a gallon and a half a day. Is the monitor just a mechanism that is programmed to change over time and really has no relation to water usage?

Answer: I don't know the mechanism that is used on your fridge but it may not be measuring use. It may instead be measuring a pressure difference between the input and output of the filter or it may have some kind of sensor that determines the filter has failed in some other way, such as by measuring the conductivity of the output water.

If this is the case then you may have only used three hundred or so gallons but the filter may still need replacing. Filters are not an exact science. The worse your water is then the less water they will filter.

We also have a Kenmore, purchased about 2 years ago with a replaceable filter. Before I did think it was on a metered system, but last year we moved and the refrigerator was in storage for almost 2 months. Sure enough, right around the 6 month mark the light changed. I'm no expert, but I would guess the light is based on a timer rather than a sophisticated meter or sensor.